Method and system for efficient matching of user profiles with audience segments

ABSTRACT

Embodiments of the present teachings disclose method, system, and programs that monetize personalized user behavioral profiles by remapping the users to audience segments related to advertisement. In the method, the users can be targeted with advertisements that are personalized and hence are more likely to lead to conversions.

BACKGROUND

1. Technical Field

The present teaching relates to methods and systems for providingcontent. Specifically, the present teaching relates to methods andsystems for providing online content.

2. Discussion of Technical Background

The Internet has made it possible for a user to electronically accessvirtually any content at anytime and from any location. With theexplosion of information, it has become more and more important toprovide users with information that is relevant to the user and not justinformation in general. Further, as users of today's society rely on theInternet as their source of information, entertainment, and/or socialconnections, e.g., news, social interaction, movies, music, etc, it iscritical to provide users with information they find valuable.

Efforts have been made to attempt to allow users to readily accessrelevant and on the point content. For example, topical portals havebeen developed that are more subject matter oriented as compared togeneric content gathering systems such as traditional search engines.Example topical portals include portals on finance, sports, news,weather, shopping, music, art, film, etc. Such topical portals allowusers to access information related to subject matters that theseportals are directed to. Users have to go to different portals to accesscontent of certain subject matter, which is not convenient and not usercentric.

Another line of efforts in attempting to enable users to easily accessrelevant content is via personalization, which aims at understandingeach user's individual likings/interests/preferences so that anindividualized user profile for each user can be set up and can be usedto select content that matches a user's interests. The underlying goalis to meet the minds of users in terms of content consumption. Userprofiles traditionally are constructed based on users' declaredinterests and/or inferred from, e.g., users' demographics. There havealso been systems that identify users' interests based on observationsmade on users' interactions with content. A typical example of such userinteraction with content is click through rate (CTR).

These traditional approaches have various shortcomings. For example,users' interests are profiled without any reference to a baseline sothat the level of interest can be more accurately estimated. Userinterests are detected in isolated application settings so that userprofiling in individual applications cannot capture a broad range of theoverall interests of a user. Such traditional approach to user profilinglead to fragmented representation of user interests without a coherentunderstanding of the users' preferences. Because profiles of the sameuser derived from different application settings are often grounded withrespect to the specifics of the applications, it is also difficult tointegrate them to generate a more coherent profile that better representthe user's interests.

User activities directed to content are traditionally observed and usedto estimate or infer users' interests. CTR is the most commonly usedmeasure to estimate users' interests. However, CTR is no longer adequateto capture users' interests particularly given that different types ofactivities that a user may perform on different types of devices mayalso reflect or implicate user's interests. In addition, user reactionsto content usually represent users' short term interests. Such observedshort term interests, when acquired piece meal, as traditionalapproaches often do, can only lead to reactive, rather than proactive,services to users. Although short term interests are important, they arenot adequate to enable understanding of the more persistent long terminterests of a user, which are crucial in terms of user retention. Mostuser interactions with content represent short term interests of theuser so that relying on such short term interest behavior makes itdifficult to expand the understanding of the increasing range ofinterests of the user. When this is in combination with the fact thatsuch collected data is always the past behavior and collected passively,it creates a personalization bubble, making it difficult, if notimpossible, to discover other interests of a user unless the userinitiates some action to reveal new interests.

Yet another line of effort to allow users to access relevant content isto pooling content that may be interested by users in accordance withtheir interests. Given the explosion of information on the Internet, itis not likely, even if possible, to evaluate all content accessible viathe Internet whenever there is a need to select content relevant to aparticular user. Thus, realistically, it is needed to identify a subsetor a pool of the Internet content based on some criteria so that contentcan be selected from this pool and recommended to users based on theirinterests for consumption.

Conventional approaches to creating such a subset of content areapplication centric. Each application carves out its own subset ofcontent in a manner that is specific to the application. For example,Amazon.com may have a content pool related to products and informationassociated thereof created/updated based on information related to itsown users and/or interests of such users exhibited when they interactwith Amazon.com. Facebook also has its own subset of content, generatedin a manner not only specific to Facebook but also based on userinterests exhibited while they are active on Facebook. As a user may beactive in different applications (e.g., Amazon.com and Facebook) andwith each application, they likely exhibit only part of their overallinterests in connection with the nature of the application. Given that,each application can usually gain understanding, at best, of partialinterests of users, making it difficult to develop a subset of contentthat can be used to serve a broader range of users' interests.

Another line of effort is directed to personalized contentrecommendation, i.e., selecting content from a content pool based on theuser's personalized profiles and recommending such identified content tothe user. Conventional solutions focus on relevance, i.e., the relevancebetween the content and the user. Although relevance is important, thereare other factors that also impact how recommendation content should beselected in order to satisfy a user's interests. Most contentrecommendation systems insert advertisement to content identified for auser for recommendation. Some traditional systems that are used toidentify insertion advertisements match content with advertisement oruser's query (also content) with advertisement, without consideringmatching based on demographics of the user with features of the targetaudience defined by advertisers. Some traditional systems match userprofiles with the specified demographics of the target audience definedby advertisers but without matching the content to be provided to theuser and the advertisement. The reason is that content is oftenclassified into taxonomy based on subject matters covered in the contentyet advertisement taxonomy is often based on desired target audiencegroups. This makes it less effective in terms of selecting the mostrelevant advertisement to be inserted into content to be recommended toa specific user.

There is a need for improvements over the conventional approaches topersonalizing content recommendation.

SUMMARY

The teachings disclosed herein relate to methods, systems, andprogramming for matching user profiles with audience segments In anembodiment a method implemented on a computing device having at leastone processor, storage, and a communication interface connected to anetwork for ranking content, is disclosed. The method comprisesobtaining, based on a first index, a user profile characterizing a user,correlating, based on the first index, the user profile with a secondindex, estimating an affinity between the user and a piece of contentassociated with the second index based on the correlated user profileand a content profile for the piece of content, and outputting the pieceof content based on the affinity measure.

In an embodiment, a system for remapping an index is disclosed. Thesystem comprises a profile obtainer for obtaining, based on a firstindex, a user profile characterizing a user, a correlator forcorrelating, based on the first index, the user profile with a secondindex, an estimator for estimating an affinity between the user and apiece of content associated with the second index based on thecorrelated user profile and a content profile for the piece of content,and an output for outputting the piece of content based on the affinitymeasure.

In an embodiment, a non-transitory computer readable medium havingrecorded thereon information for remapping an index is disclosed themedium, when read by a computer, causes the computer to obtain, based ona first index, a user profile characterizing a user, correlate, based onthe first index, the user profile with a second index, estimate anaffinity between the user and a piece of content associated with thesecond index based on the correlated user profile and a content profilefor the piece of content, and output the piece of content based on theaffinity measure.

In another embodiment, the first index is a content taxonomy and thesecond index is an advertisement taxonomy. In still another embodimentthe piece of content associated with the second index is anadvertisement. In still another embodiment, the first index is auniversal interest index.

In an embodiment, a method to monetize user behavior implemented on acomputing device having at least one processor, storage, and acommunication interface connected to a network for ranking content isdisclosed. The method comprising. obtaining, a user profilecharacterizing a user, mapping the user profile to an advertisingaudience segments, estimating an affinity between the user profile andthe advertising audience segments, identifying advertising contentassociated with the advertising audience segments and, outputting the apiece of the advertising content based on the estimated affinity.

BRIEF DESCRIPTION OF THE DRAWINGS

The methods, systems and/or programming described herein are furtherdescribed in terms of exemplary embodiments. These exemplary embodimentsare described in detail with reference to the drawings. Theseembodiments are non-limiting exemplary embodiments, in which likereference numerals represent similar structures throughout the severalviews of the drawings, and wherein:

FIG. 1 depicts an exemplary system diagram for personalized contentrecommendation, according to an embodiment of the present teaching;

FIG. 2 is a flowchart of an exemplary process for personalized contentrecommendation, according to an embodiment of the present teaching;

FIG. 3 illustrates exemplary types of context information;

FIG. 4 depicts an exemplary diagram of a content pool generation/updateunit, according to an embodiment of the present teaching;

FIG. 5 is a flowchart of an exemplary process of creating a contentpool, according to an embodiment of the present teaching;

FIG. 6 is a flowchart of an exemplary process for updating a contentpool, according to an embodiment of the present teaching;

FIG. 7 depicts an exemplary diagram of a user understanding unit,according to an embodiment of the present teaching;

FIG. 8 is a flowchart of an exemplary process for generating a baselineinterest profile, according to an embodiment of the present teaching;

FIG. 9 is a flowchart of an exemplary process for generating apersonalized user profile, according to an embodiment of the presentteaching;

FIG. 10 depicts an exemplary system diagram for a content ranking unit,according to an embodiment of the present teaching;

FIG. 11 is a flowchart of an exemplary process for the content rankingunit, according to an embodiment of the present teaching;

FIG. 12 depicts an exemplary system diagram of a portions of apersonalization system, according to an embodiment of the presentteaching;

FIG. 13 depicts the steps in an advertising taxonomy re-mapping system,according to an embodiment of the present teaching;

FIG. 14 depicts a diagram of the portions of a user's profile in anadvertising taxonomy re-mapping system, according to an embodiment ofthe present teaching;

FIG. 15 depicts the steps in generating weighted audience segments in anadvertising taxonomy re-mapping system, according to an embodiment ofthe present teaching;

FIG. 16 depicts a portion of an exemplary content taxonomy in anadvertising taxonomy re-mapping system, according to an embodiment ofthe present teaching;

FIG. 17 depicts a portion of a knowledge archive, according to anembodiment of the present teaching;

FIG. 18 depicts a portion of an exemplary Wikipedia content archive,according to an embodiment of the present teaching;

FIG. 19 depicts a diagram of a content/advertisement taxonomy correlaterin an advertising taxonomy re-mapping system, according to an embodimentof the present teaching;

FIG. 20 depicts a general computer architecture on which the presentteaching can be implemented.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and/or circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

The present teaching relates to personalizing on-line contentrecommendations to a user. Particularly, the present teaching relates toa system, method, and/or programs for personalized contentrecommendation that addresses the shortcomings associated theconventional content recommendation solutions in personalization,content pooling, and recommending personalized content.

With regard to personalization, the present teaching identifies a user'sinterests with respect to a universal interest space, defined via knownconcept archives such as Wikipedia and/or content taxonomy. Using such auniversal interest space, interests of users, exhibited in differentapplications and via different platforms, can be used to establish ageneral population's profile as a baseline against which individualuser's interests and levels thereof can be determined. For example,users active in a third party application such as Facebook or Twitterand the interests that such users exhibited in these third partyapplications can be all mapped to the universal interest space and thenused to compute a baseline interest profile of the general population.Specifically, each user's interests observed with respect to eachdocument covering certain subject matters or concepts can be mapped to,e.g., Wikipedia or certain content taxonomy. A high dimensional vectorcan be constructed based on the universal interest space in which eachattribute of the vector corresponds to a concept in the universal spaceand the value of the attribute may corresponds to an evaluation of theuser's interest in this particular concept. The general baselineinterest profile can be derived based on all vectors represent thepopulation. Each vector representing an individual can be normalizedagainst the baseline interest profile so that the relative level ofinterests of the user with respect to the concepts in the universalinterest space can be determined. This enables better understanding ofthe level of interests of the user in different subject matters withrespect to a more general population and result in enhancedpersonalization for content recommendation. Rather than characterizingusers' interests merely according to proprietary content taxonomy, as isoften done in the prior art, the present teaching leverages publicconcept archives, such as Wikipedia or online encyclopedia, to define auniversal interest space in order to profile a user's interests in amore coherent manner. Such a high dimensional vector captures the entireinterest space of every user, making person-to-person comparison as topersonal interests more effective. Profiling a user and in this manneralso leads to efficient identification of users who share similarinterests. In addition, content may also be characterized in the sameuniversal interest space, e.g., a high dimensional vector against theconcepts in the universal interest space can also be constructed withvalues in the vector indicating whether the content covers each of theconcepts in the universal interest space. By characterizing users andcontent in the same space in a coherent way, the affinity between a userand a piece of content can be determined via, e.g., a dot product of thevector for the user and the vector for the content.

The present teaching also leverages short term interests to betterunderstand long term interests of users. Short term interests can beobserved via user online activities and used in online contentrecommendation, the more persistent long term interests of a user canhelp to improve content recommendation quality in a more robust mannerand, hence, user retention rate. The present teaching disclosesdiscovery of long term interests as well as short term interests.

To improve personalization, the present teaching also discloses ways toimprove the ability to estimate a user's interest based on a variety ofuser activities. This is especially useful because meaningful useractivities often occur in different settings, on different devices, andin different operation modes. Through such different user activities,user engagement to content can be measured to infer users' interests.Traditionally, clicks and click through rate (CTR) have been used toestimate users' intent and infer users' interests. CTR is simply notadequate in today's world. Users may dwell on a certain portion of thecontent, the dwelling may be for different lengths of time, users mayscroll along the content and may dwell on a specific portion of thecontent for some length of time, users may scroll down at differentspeeds, users may change such speed near certain portions of content,users may skip certain portion of content, etc. All such activities mayhave implications as to users' engagement to content. Such engagementcan be utilized to infer or estimate a user's interests. The presentteaching leverages a variety of user activities that may occur acrossdifferent device types in different settings to achieve betterestimation of users' engagement in order to enhance the ability ofcapturing a user's interests in a more reliable manner.

Another aspect of the present teaching with regard to personalization isits ability to explore unknown interests of a user by generating probingcontent. Traditionally, user profiling is based on either user providedinformation (e.g., declared interests) or passively observed pastinformation such as the content that the user has viewed, reactions tosuch content, etc. Such prior art schemes can lead to a personalizationbubble where only interests that the user revealed can be used forcontent recommendation. Because of that, the only user activities thatcan be observed are directed to such known interests, impeding theability to understand the overall interest of a user. This is especiallyso considering the fact that users often exhibit different interests(mostly partial interests) in different application settings. Thepresent teaching discloses ways to generate probing content withconcepts that is currently not recognized as one of the user's interestsin order to explore the user's unknown interests. Such probing contentis selected and recommended to the user and user activities directed tothe probing content can then be analyzed to estimate whether the userhas other interests. The selection of such probing content may be basedon a user's current known interests by, e.g., extrapolating the user'scurrent interests. For example, for some known interests of the user(e.g., the short term interests at the moment), some probing concepts inthe universal interest space, for which the user has not exhibitedinterests in the past, may be selected according to some criteria (e.g.,within a certain distance from the user's current known interest in ataxonomy tree) and content related to such probing concepts may then beselected and recommended to the user. Another way to identify probingconcept (corresponding to unknown interest of the user) may be throughthe user's cohorts. For instance, a user may share certain interestswith his/her cohorts but some members of the circle may have someinterests that the user has never exhibited before. Such un-sharedinterests with cohorts may be selected as probing unknown interests forthe user and content related to such probing unknown interests may thenbe selected as probing content to be recommended to the user. In thismanner, the present teaching discloses a scheme by which a user'sinterests can be continually probed and understood to improve thequality of personalization. Such managed probing can also be combinedwith random selection of probing content to allow discovery of unknowninterests of the user that are far removed from the user's current knowninterests.

A second aspect of recommending quality personalized content is to builda content pool with quality content that covers subject mattersinteresting to users. Content in the content pool can be rated in termsof the subject and/or the performance of the content itself. Forexample, content can be characterized in terms of concepts it disclosesand such a characterization may be generated with respect to theuniversal interest space, e.g., defined via concept archive(s) such ascontent taxonomy and/or Wikipedia and/or online encyclopedia, asdiscussed above. For example, each piece of content can be characterizedvia a high dimensional vector with each attribute of the vectorcorresponding to a concept in the interest universe and the value of theattribute indicates whether and/or to what degree the content covers theconcept. When a piece of content is characterized in the same universalinterest space as that for user's profile, the affinity between thecontent and a user profile can be efficiently determined.

Each piece of content in the content pool can also be individuallycharacterized in terms of other criteria. For example, performancerelated measures, such as popularity of the content, may be used todescribe the content. Performance related characterizations of contentmay be used in both selecting content to be incorporated into thecontent pool as well as selecting content already in the content poolfor recommendation of personalized content for specific users. Suchperformance oriented characterizations of each piece of content maychange over time and can be assessed periodically and can be done basedon users' activities. Content pool also changes over time based onvarious reasons, such as content performance, change in users'interests, etc. Dynamically changed performance characterization ofcontent in the content pool may also be evaluated periodically ordynamically based on performance measures of the content so that thecontent pool can be adjusted over time, i.e., by removing lowperformance content pieces, adding new content with good performance, orupdating content.

To grow the content pool, the present teaching discloses ways tocontinually discover both new content and new content sources from whichinteresting content may be accessed, evaluated, and incorporated intothe content pool. New content may be discovered dynamically viaaccessing information from third party applications which users use andexhibit various interests. Examples of such third party applicationsinclude Facebook, Twitter, Microblogs, or YouTube. New content may alsobe added to the content pool when some new interest or an increasedlevel of interests in some subject matter emerges or is predicted basedon the occurrence of certain (spontaneous) events. One example is thecontent about the life of Pope Benedict, which in general may not be atopic of interests to most users but likely will be in light of thesurprising announcement of Pope Benedict's resignation. Such dynamicadjustment to the content pool aims at covering a dynamic (and likelygrowing) range of interests of users, including those that are, e.g.,exhibited by users in different settings or applications or predicted inlight of context information. Such newly discovered content may then beevaluated before it can be selected to be added to the content pool.

Certain content in the content pool, e.g., journals or news, need to beupdated over time. Conventional solutions usually update such contentperiodically based on a fixed schedule. The present teaching disclosesthe scheme of dynamically determining the pace of updating content inthe content pool based on a variety of factors. Content update may beaffected by context information. For example, the frequency at which apiece of content scheduled to be updated may be every 2 hours, but thisfrequency can be dynamically adjusted according to, e.g., an explosiveevent such as an earthquake. As another example, content from a socialgroup on Facebook devoted to Catholicism may normally be updated daily.When Pope Benedict's resignation made the news, the content from thatsocial group may be updated every hour so that interested users can keeptrack of discussions from members of this social group. In addition,whenever there are newly identified content sources, it can be scheduledto update the content pool by, e.g., crawling the content from the newsources, processing the crawled content, evaluating the crawled content,and selecting quality new content to be incorporated into the contentpool. Such a dynamically updated content pool aims at growing incompatible with the dynamically changing users' interests in order tofacilitate quality personalized content recommendation.

Another key to quality personalized content recommendation is the aspectof identifying quality content that meets the interests of a user forrecommendation. Previous solutions often emphasize mere relevance of thecontent to the user when selecting content for recommendation. Inaddition, traditional relevance based content recommendation was mostlybased on short term interests of the user. This not only leads to acontent recommendation bubble, i.e., known short interests causerecommendations limited to the short term interests and reactions tosuch short term interests centric recommendations cycle back to theshort term interests that start the process. This bubble makes itdifficult to come out of the circle to recommend content that can servenot only the overall interests but also long term interests of users.The present teaching combines relevance with performance of the contentso that not only relevant but also quality content can be selected andrecommended to users in a multi-stage ranking system.

In addition, to identify recommended content that can serve a broadrange of interests of a user, the present teaching relies on both shortterm and long term interests of the user to identify user-contentaffinity in order to select content that meets a broader range of users'interests to be recommended to the user.

In content recommendation, monetizing content such as advertisements areusually also selected as part of the recommended content to a user.Traditional approaches often select ads based on content in which theads are to be inserted. Some traditional approaches also rely on userinput such as queries to estimate what ads likely can maximize theeconomic return. These approaches select ads by matching the taxonomy ofthe query or the content retrieved based on the query with the contenttaxonomy of the ads. However, content taxonomy is commonly known not tocorrespond with advertisement taxonomy, which advertisers use to targetat certain audience. As such, selecting ads based on content taxonomydoes not serve to maximize the economic return of the ads to be insertedinto content and recommended to users. The present teaching disclosesmethod and system to build a linkage between content taxonomy andadvertisement taxonomy so that ads that are not only relevant to auser's interests but also the interests of advertisers can be selected.In this way, the recommended content with ads to a user can both servethe user's interests and at the same time to allow the content operatorto enhance monetization via ads.

Yet another aspect of personalized content recommendation of the presentteaching relates to recommending probing content that is identified byextrapolating the currently known user interests. Traditional approachesrely on selecting either random content beyond the currently known userinterests or content that has certain performance such as a high levelof click activities. Random selection of probing content presents a lowpossibility to discover a user's unknown interests. Identifying probingcontent by choosing content for which a higher level of activities areobserved is also problematic because there can be many pieces of contentthat a user may potentially be interested but there is a low level ofactivities associated therewith. The present teaching discloses ways toidentify probing content by extrapolating the currently known interestwith the flexibility of how far removed from the currently knowninterests. This approach also incorporates the mechanism to identifyquality probing content so that there is an enhanced likelihood todiscover a user's unknown interests. The focus of interests at anymoment can be used as an anchor interest based on which probinginterests (which are not known to be interests of the user) can beextrapolated from the anchor interests and probing content can beselected based on the probing interests and recommended to the usertogether with the content of the anchor interests. Probinginterests/content may also be determined based on other considerationssuch as locale, time, or device type. In this way, the disclosedpersonalized content recommendation system can continually explore anddiscover unknown interests of a user to understand better the overallinterests of the user in order to expand the scope of service.

Additional novel features will be set forth in part in the descriptionwhich follows, and in part will become apparent to those skilled in theart upon examination of the following and the accompanying drawings ormay be learned by production or operation of the examples. Theadvantages of the present teachings may be realized and attained bypractice or use of various aspects of the methodologies,instrumentalities and combinations set forth in the detailed examplesdiscussed below.

FIG. 1 depicts an exemplary system diagram 10 for personalized contentrecommendation to a user 105, according to an embodiment of the presentteaching. System 10 comprises a personalized content recommendationmodule 100, which comprises numerous sub modules, content sources 110,knowledge archives 115, third party platforms 120, and advertisers 125with advertisement taxonomy 127 and advertisement database 126. Contentsources 110 may be any source of on-line content such as on-line news,published papers, blogs, on-line tabloids, magazines, audio content,image content, and video content. It may be content from contentprovider such as Yahoo! Finance, Yahoo! Sports, CNN, and ESPN. It may bemulti-media content or text or any other form of content comprised ofwebsite content, social media content, such as Facebook, twitter,Reddit, etc, or any other content rich provider. It may be licensedcontent from providers such AP and Reuters. It may also be contentcrawled and indexed from various sources on the Internet. Contentsources 110 provide a vast array of content to the personalized contentrecommendation module 100 of system 10.

Knowledge archives 115 may be an on-line encyclopedia such as Wikipediaor indexing system such as an on-line dictionary. On-line conceptarchives 115 may be used for its content as well as its categorizationor indexing systems. Knowledge archives 115 provide extensiveclassification system to assist with the classification of both theuser's 105 preferences as well as classification of content. Knowledgeconcept archives, such as Wikipedia may have hundreds of thousands tomillions of classifications and sub-classifications. A classification isused to show the hierarchy of the category. Classifications serve twomain purposes. First they help the system understand how one categoryrelates to another category and second, they help the system maneuverbetween higher levels on the hierarchy without having to move up anddown the subcategories. The categories or classification structure foundin knowledge archives 115 is used for multidimensional content vectorsas well as multidimensional user profile vectors which are utilized bypersonalized content recommendation module 100 to match personalizedcontent to a user 105. Third party platforms 120 maybe any third partyapplications including but not limited to social networking sites likeFacebook, Twitter, LinkedIn, Google+. It may include third party mailservers such as GMail or Bing Search. Third party platforms 120 provideboth a source of content as well as insight into a user's personalpreferences and behaviors.

Advertisers 125 are coupled with the ad content database 126 as well asan ads classification system or ad. taxonomy 127 intended for classifiedadvertisement content. Advertisers 125 may provide streaming content,static content, and sponsored content. Advertising content may be placedat any location on a personalized content page and may be presented bothas part of a content stream as well as a standalone advertisement,placed strategically around or within the content stream.

Personalized content recommendation module 100 comprises applications130, content pool 135, content pool generation/update unit 140,concept/content analyzer 145, content crawler 150, unknown interestexplorer 215, user understanding unit 155, user profiles 160, contenttaxonomy 165, context information analyzer 170, user event analyzer 175,third party interest analyzer 190, social media content sourceidentifier 195, advertisement insertion unit 200 andcontent/advertisement/taxonomy correlator 205. These components areconnected to achieve personalization, content pooling, and recommendingpersonalized content to a user. For example, the content ranking unit210 works in connection with context information analyzer 170, theunknown interest explorer 215, and the ad insertion unit 200 to generatepersonalized content to be recommended to a user with personalized adsor probing content inserted. To achieve personalization, the userunderstanding unit 155 works in connection with a variety of componentsto dynamically and continuously update the user profiles 160, includingcontent taxonomy 165, the knowledge archives 115, user event analyzer175, and the third party interest analyzer 190. Various components areconnected to continuously maintain a content pool, including the contentpool generation/update unit 140, user event analyzer 175, social mediacontent source identifier 195, content/concept analyzer 145, contentcrawler 150, the content taxonomy 165, as well as user profiles 160.

Personalized content recommendation module 100 is triggered when user105 engages with system 10 through applications 130. Applications 130may receive information in the form of a user id, cookies, log ininformation from user 105 via some form of computing device. User 105may access system 10 via a wired or wireless device and may bestationary or mobile. User 105 may interface with the applications 130on a tablet, a Smartphone, a laptop, a desktop or any other computingdevice which may be embedded in devices such as watches, eyeglasses, orvehicles. In addition to receiving insights from the user 105 about whatinformation the user 105 might be interested, applications 130 providesinformation to user 105 in the form of personalized content stream. Userinsights might be user search terms entered to the system, declaredinterests, user clicks on a particular article or subject, user dwelltime or scroll over of particular content, user skips with respect tosome content, etc. User insights may be a user indication of a like, ashare, or a forward action on a social networking site, such asFacebook, or even peripheral activities such as print or scan of certaincontent. All of these user insights or events are utilized by thepersonalized content recommendation module 100 to locate and customizecontent to be presented to user 105. User insights received viaapplications 130 are used to update personalized profiles for userswhich may be stored in user profiles 160. User profiles 160 may bedatabase or a series of databases used to store personalized userinformation on all the users of system 10. User profiles 160 may be aflat or relational database and may be stored in one or more locations.Such user insights may also be used to determine how to dynamicallyupdate the content in the content pool 135.

A specific user event received via applications 130 is passed along touser event analyzer 175, which analyzes the user event information andfeeds the analysis result with event data to the user understanding unit155 and/or the content pool generation/update unit 140. Based on suchuser event information, the user understanding unit 155 estimates shortterm interests of the user and/or infer user's long term interests basedon behaviors exhibited by user 105 over long or repetitive periods. Forexample, a long term interest may be a general interest in sports, whereas a short term interest may be related to a unique sports event, suchas the Super Bowl at a particular time. Over time, a user's long terminterest may be estimated by analyzing repeated user events. A user who,during every engagement with system 10, regularly selects contentrelated to the stock market may be considered as having a long terminterest in finances. In this case, system 10 accordingly, may determinethat personalized content for user 105 should contain content related tofinance. Contrastingly, short term interest may be determined based onuser events which may occur frequently over a short period, but which isnot something the user 105 is interested in the long term. For example,a short term interest may reflect the momentary interest of a user whichmay be triggered by something the user saw in the content but such aninterest may not persist over time. Both short and long term interestare important in terms of identifying content that meets the desire ofthe user 105, but need to be managed separately because of thedifference in their nature as well as how they influence the user.

In some embodiments, short term interests of a user may be analyzed topredict the user's long term interests. To retain a user, it isimportant to understand the user's persistent or long term interests. Byidentifying user 105's short term interest and providing him/her with aquality personalized experience, system 10 may convert an occasionaluser into a long term user. Additionally, short term interest may trendinto long term interest and vice versa. The user understanding unit 155provides the capability of estimating both short and long terminterests.

The user understanding unit 155 gathers user information from multiplesources, including all the user's events, and creates one or moremultidimensional personalization vectors. In some embodiments, the userunderstanding unit 155 receives inferred characteristics about the user105 based on the user events, such as the content he/she views, selfdeclared interests, attributes or characteristics, user activities,and/or events from third party platforms. In an embodiment, the userunderstanding unit 155 receives inputs from social media content sourceidentifier 195. Social media content source identifier 195 relies onuser 105's social media content to personalize the user's profile. Byanalyzing the user's social media pages, likes, shares, etc, socialmedia content source identifier 195 provides information for userunderstanding unit 155. The social media content source identifier 195is capable of recognizing new content sources by identifying, e.g.,quality curators on social media platforms such as Twitter, Facebook, orblogs, and enables the personalized content recommendation module 100 todiscover new content sources from where quality content can be added tothe content pool 135. The information generated by social media contentsource identifier 195 may be sent to a content/concept analyzer 145 andthen mapped to specific category or classification based on contenttaxonomy 165 as well as a knowledge archives 115 classification system.

The third party interest analyzer 190 leverages information from otherthird party platforms about users active on such third party platforms,their interests, as well as content these third party users to enhancethe performance of the user understanding unit 155. For example, wheninformation about a large user population can be accessed from one ormore third party platforms, the user understanding unit 155 can rely ondata about a large population to establish a baseline interest profileto make the estimation of the interests of individual users more preciseand reliable, e.g., by comparing interest data with respect to aparticular user with the baseline interest profile which will capturethe user's interests with a high level of certainty.

When new content is identified from content source 110 or third partyplatforms 120, it is processed and its concepts are analyzed. Theconcepts can be mapped to one or more categories in the content taxonomy165 and the knowledge archives 115. The content taxonomy 165 is anorganized structure of concepts or categories of concepts and it maycontain a few hundred classifications of a few thousand. The knowledgearchives 115 may provide millions of concepts, which may or may not bestructures in a similar manner as the content taxonomy 165. Such contenttaxonomy and knowledge archives may serve as a universal interest space.Concepts estimated from the content can be mapped to a universalinterest space and a high dimensional vector can be constructed for eachpiece of content and used to characterize the content. Similarly, foreach user, a personal interest profile may also be constructed, mappingthe user's interests, characterized as concepts, to the universalinterest space so that a high dimensional vector can be constructed withthe user's interests levels populated in the vector.

Content pool 135 may be a general content pool with content to be usedto serve all users. The content pool 135 may also be structured so thatit may have personalized content pool for each user. In this case,content in the content pool is generated and retained with respect toeach individual user. The content pool may also be organized as a tieredsystem with both the general content pool and personalized individualcontent pools for different users. For example, in each content pool fora user, the content itself may not be physically present but isoperational via links, pointers, or indices which provide references towhere the actual content is stored in the general content pool.

Content pool 135 is dynamically updated by content poolgeneration/update module 140. Content in the content pool comes and goand decisions are made based on the dynamic information of the users,the content itself, as well as other types of information. For example,when the performance of content deteriorates, e.g., low level ofinterests exhibited from users, the content pool generation/update unit140 may decide to purge it from the content pool. When content becomesstale or outdated, it may also be removed from the content pool. Whenthere is a newly detected interest from a user, the content poolgeneration/update unit 140 may fetch new content aligning with the newlydiscovered interests. User events may be an important source of makingobservations as to content performance and user interest dynamics. Useractivities are analyzed by the user event analyzer 175 and suchInformation is sent to the content pool generation/update unit 140. Whenfetching new content, the content pool generation/update unit 140invokes the content crawler 150 to gather new content, which is thenanalyzed by the content/concept analyzer 145, then evaluated by thecontent pool generation/update unit 140 as to its quality andperformance before it is decided whether it will be included in thecontent pool or not. Content may be removed from content pool 135because it is no longer relevant, because other users are notconsidering it to be of high quality or because it is no longer timely.As content is constantly changing and updating content pool 135 isconstantly changing and updating providing user 105 with a potentialsource for high quality, timely personalized content.

In addition to content, personalized content recommendation module 100provides for targeted or personalized advertisement content fromadvertisers 125. Advertisement database 126 houses advertising contentto be inserted into a user's content stream. Advertising content from addatabase 126 is inserted into the content stream via Content rankingunit 210. The personalized selection of advertising content can be basedon the user's profile. Content/advertisement/user taxonomy correlator205 may re-project or map a separate advertisement taxonomy 127 to thetaxonomy associated with the user profiles 160.Content/advertisement/user taxonomy correlator 205 may apply a straightmapping or may apply some intelligent algorithm to the re-projection todetermine which of the users may have a similar or related interestbased on similar or overlapping taxonomy categories.

Content ranking unit 210 generates the content stream to be recommendedto user 105 based on content, selected from content pool 135 based onthe user's profile, as well as advertisement, selected by theadvertisement insertion unit 200. The content to be recommended to theuser 105 may also be determined, by the content ranking unit 210, basedon information from the context information analyzer 170. For example,if a user is currently located in a beach town which differs from thezip code in the user's profile, it can be inferred that the user may beon vacation. In this case, information related to the locale where theuser is currently in may be forwarded from the context informationanalyzer to the Content ranking unit 210 so that it can select contentthat not only fit the user's interests but also is customized to thelocale. Other context information include day, time, and device type.The context information can also include an event detected on the devicethat the user is currently using such as a browsing event of a websitedevoted to fishing. Based on such a detected event, the momentaryinterest of the user may be estimated by the context informationanalyzer 170, which may then direct the Content ranking unit 210 togather content related to fishing amenities in the locale the user is infor recommendation.

The personalized content recommendation module 100 can also beconfigured to allow probing content to be included in the content to berecommended to the user 105, even though the probing content does notrepresent subject matter that matches the current known interests of theuser. Such probing content is selected by the unknown interest explorer215. Once the probing content is incorporated in the content to berecommended to the user, information related to user activities directedto the probing content (including no action) is collected and analyzedby the user event analyzer 175, which subsequently forwards the analysisresult to long/short term interest identifiers 180 and 185. If ananalysis of user activities directed to the probing content reveals thatthe user is or is not interested in the probing content, the userunderstanding unit 155 may then update the user profile associated withthe probed user accordingly. This is how unknown interests may bediscovered. In some embodiments, the probing content is generated basedon the current focus of user interest (e.g., short term) byextrapolating the current focus of interests. In some embodiments, theprobing content can be identified via a random selection from thegeneral content, either from the content pool 135 or from the contentsources 110, so that an additional probing can be performed to discoverunknown interests.

To identify personalized content for recommendation to a user, thecontent ranking unit 210 takes all these inputs and identify contentbased on a comparison between the user profile vector and the contentvector in a multiphase ranking approach. The selection may also befiltered using context information. Advertisement to be inserted as wellas possibly probing content can then be merged with the selectedpersonalized content.

FIG. 2 is a flowchart of an exemplary process for personalized contentrecommendation, according to an embodiment of the present teaching.Content taxonomy is generated at 205. Content is accessed from differentcontent sources and analyzed and classified into different categories,which can be pre-defined. Each category is given some labels and thendifferent categories are organized into some structure, e.g., ahierarchical structure. A content pool is generated at 210. Differentcriteria may be applied when the content pool is created. Examples ofsuch criteria include topics covered by the content in the content pool,the performance of the content in the content pool, etc. Sources fromwhich content can be obtained to populate the content pool includecontent sources 110 or third party platforms 120 such as Facebook,Twitter, blogs, etc. FIG. 3 provides a more detailed exemplary flowchartrelated to content pool creation, according to an embodiment of thepresent teaching. User profiles are generated at 215 based on, e.g.,user information, user activities, identified short/long term interestsof the user, etc. The user profiles may be generated with respect to abaseline population interest profile, established based on, e.g.,information about third party interest, knowledge archives, and contenttaxonomies.

Once the user profiles and the content pool are created, when the system10 detects the presence of a user, at 220, the context information, suchas locale, day, time, may be obtained and analyzed, at 225. FIG. 4illustrates exemplary types of context information. Based on thedetected user's profile, optionally context information, personalizedcontent is identified for recommendation. A high level exemplary flowfor generating personalized content for recommendation is presented inFIG. 5. Such gathered personalized content may be ranked and filtered toachieve a reasonable size as to the amount of content forrecommendation. Optionally (not shown), advertisement as well as probingcontent may also be incorporated in the personalized content. Suchcontent is then recommended to the user at 230.

User reactions or activities with respect to the recommended content aremonitored, at 235, and analyzed at 240. Such events or activitiesinclude clicks, skips, dwell time measured, scroll location and speed,position, time, sharing, forwarding, hovering, motions such as shaking,etc. It is understood that any other events or activities may bemonitored and analyzed. For example, when the user moves the mousecursor over the content, the title or summary of the content may behighlighted or slightly expanded. In anther example, when a userinteracts with a touch screen by her/his finger[s], any known touchscreen user gestures may be detected. In still another example, eyetracking on the user device may be another user activity that ispertinent to user behaviors and can be detected. The analysis of suchuser events includes assessment of long term interests of the user andhow such exhibited short term interests may influence the system'sunderstanding of the user's long term interests. Information related tosuch assessment is then forwarded to the user understanding unit 155 toguide how to update, at 255, the user's profile. At the same time, basedon the user's activities, the portion of the recommended content thatthe user showed interests are assessed, at 245, and the result of theassessment is then used to update, at 250, the content pool. Forexample, if the user shows interests on the probing content recommended,it may be appropriate to update the content pool to ensure that contentrelated to the newly discovered interest of the user will be included inthe content pool.

FIG. 3 illustrates different types of context information that may bedetected and utilized in assisting to personalize content to berecommended to a user. In this illustration, context information mayinclude several categories of data, including, but not limited to, time,space, platform, and network conditions. Time related information can betime of the year (e.g., a particular month from which season can beinferred), day of a week, specific time of the day, etc. Suchinformation may provide insights as to what particular set of interestsassociated with a user may be more relevant. To infer the particularinterests of a user at a specific moment may also depend on the localethat the user is in and this can be reflected in the space relatedcontext information, such as which country, what locale (e.g., touristtown), which facility the user is in (e.g., at a grocery store), or eventhe spot the user is standing at the moment (e.g., the user may bestanding in an aisle of a grocery store where cereal is on display).Other types of context information includes the specific platformrelated to the user's device, e.g., Smartphone, Tablet, laptop, desktop,bandwidth/data rate allowed on the user's device, which will impact whattypes of content may be effectively presented to the user. In addition,the network related information such as state of the network where theuser's device is connected to, the available bandwidth under thatcondition, etc. may also impact what content should be recommended tothe user so that the user can receive or view the recommended contentwith reasonable quality.

FIG. 4 depicts an exemplary system diagram of the content poolgeneration/update unit 140, according to an embodiment of the presentteaching. The content pool 135 can be initially generated and thenmaintained according to the dynamics of the users, contents, and needsdetected. In this illustration, the content pool generation/update unit140 comprises a content/concept analyzing control unit 410, a contentperformance estimator 420, a content quality evaluation unit 430, acontent selection unit 480, which will select appropriate content toplace into the content pool 135. In addition, to control how content isto be updated, the content pool generation/update unit 140 also includesa user activity analyzer 440, a content status evaluation unit 450, anda content update control unit 490.

The content/concept analyzing control unit 410 interfaces with thecontent crawler 150 (FIG. 1) to obtain candidate content that is to beanalyzed to determine whether the new content is to be added to thecontent pool. The content/concept analyzing control unit 410 alsointerfaces with the content/concept analyzer 145 (see FIG. 1) to get thecontent analyzed to extract concepts or subjects covered by the content.Based on the analysis of the new content, a high dimensional vector forthe content profile can be computed via, e.g., by mapping the conceptsextracted from the content to the universal interest space, e.g.,defined via Wikipedia or other content taxonomies. Such a contentprofile vector can be compared with user profiles 160 to determinewhether the content is of interest to users. In addition, content isalso evaluated in terms of its performance by the content performanceestimator 420 based on, e.g., third party information such as activitiesof users from third party platforms so that the new content, althoughnot yet acted upon by users of the system, can be assessed as to itsperformance. The content performance information may be stored, togetherwith the content's high dimensional vector related to the subject of thecontent, in the content profile 470. The performance assessment is alsosent to the content quality evaluation unit 430, which, e.g., will rankthe content in a manner consistent with other pieces of content in thecontent pool. Based on such rankings, the content selection unit 480then determines whether the new content is to be incorporated into thecontent pool 135.

To dynamically update the content pool 135, the content poolgeneration/update unit 140 may keep a content log 460 with respect toall content presently in the content pool and dynamically update the logwhen more information related to the performance of the content isreceived. When the user activity analyzer 440 receives informationrelated to user events, it may log such events in the content log 460and perform analysis to estimate, e.g., any change to the performance orpopularity of the relevant content over time. The result from the useractivity analyzer 440 may also be utilized to update the contentprofiles, e.g., when there is a change in performance. The contentstatus evaluation unit 450 monitors the content log and the contentprofile 470 to dynamically determine how each piece of content in thecontent pool 135 is to be updated. Depending on the status with respectto a piece of content, the content status evaluation unit 450 may decideto purge the content if its performance degrades below a certain level.It may also decide to purge a piece of content when the overall interestlevel of users of the system drops below a certain level. For contentthat requires update, e.g., news or journals, the content statusevaluation unit 450 may also control the frequency 455 of the updatesbased on the dynamic information it receives. The content update controlunit 490 carries out the update jobs based on decisions from the contentstatus evaluation unit 450 and the frequency at which certain contentneeds to be updated. The content update control unit 490 may alsodetermine to add new content whenever there is peripheral informationindicating the needs, e.g., there is an explosive event and the contentin the content pool on that subject matter is not adequate. In thiscase, the content update control unit 490 analyzes the peripheralinformation and if new content is needed, it then sends a control signalto the content/concept analyzing control unit 410 so that it caninterface with the content crawler 150 to obtain new content.

FIG. 5 is a flowchart of an exemplary process of creating the contentpool, according to an embodiment of the present teaching. Content isaccessed at 510 from content sources, which include content from contentportals such as Yahoo!, general Internet sources such as web sites orFTP sites, social media platforms such as Twitter, or other third partyplatforms such as Facebook. Such accessed content is evaluated, at 520,as to various considerations such as performance, subject matterscovered by the content, and how it fit users' interests. Based on suchevaluation, certain content is selected to generate, at 530, the contentpool 135, which can be for the general population of the system or canalso be further structured to create sub content pools, each of whichmay be designated to a particular user according to the user'sparticular interests. At 540, it is determined whether user-specificcontent pools are to be created. If not, the general content pool 135 isorganized (e.g., indexed or categorized) at 580. If individual contentpools for individual users are to be created, user profiles are obtainedat 550, and with respect to each user profile, a set of personalizedcontent is selected at 560 that is then used to create a sub contentpool for each such user at 570. The overall content pool and the subcontent pools are then organized at 580.

FIG. 6 is a flowchart of an exemplary process for updating the contentpool 135, according to an embodiment of the present teaching. Dynamicinformation is received at 610 and such information includes useractivities, peripheral information, user related information, etc. Basedon the received dynamic information, the content log is updated at 620and the dynamic information is analyzed at 630. Based on the analysis ofthe received dynamic information, it is evaluated, at 640, with respectto the content implicated by the dynamic information, as to the changeof status of the content. For example, if received information isrelated to user activities directed to specific content pieces, theperformance of the content piece may need to be updated to generate anew status of the content piece. It is then determined, at 650, whetheran update is needed. For instance, if the dynamic information from aperipheral source indicates that content of certain topic may have ahigh demand in the near future, it may be determined that new content onthat topic may be fetched and added to the content pool. In this case,at 660, content that needs to be added is determined. In addition, ifthe performance or popularity of a content piece has just dropped belowan acceptable level, the content piece may need to be purged from thecontent pool 135. Content to be purged is selected at 670. Furthermore,when update is needed for regularly refreshed content such as journal ornews, the schedule according to which update is made may also be changedif the dynamic information received indicates so. This is achieved at680.

FIG. 7 depicts an exemplary diagram of the user understanding unit 155,according to an embodiment of the present teaching. In this exemplaryconstruct, the user understanding unit 155 comprises a baseline interestprofile generator 710, a user profile generator 720, a userintent/interest estimator 740, a short term interest identifier 750 anda long term interest identifier 760. In operation, the userunderstanding unit 155 takes various input and generates user profiles160 as output. Its input includes third party data such as users'information from such third party platforms as well as content suchusers accessed and expressed interests, concepts covered in such thirdparty data, concepts from the universal interest space (e.g., Wikipediaor content taxonomy), information about users for whom the personalizedprofiles are to be constructed, as well as information related to theactivities of such users. Information from a user for whom apersonalized profile is to be generated and updated includesdemographics of the user, declared interests of the user, etc.Information related to user events includes the time, day, location atwhich a user conducted certain activities such as clicking on a contentpiece, long dwell time on a content piece, forwarding a content piece toa friend, etc.

In operation, the baseline interest profile generator 710 accessinformation about a large user population including users' interests andcontent they are interested in from one or more third party sources(e.g., Facebook). Content from such sources is analyzed by thecontent/concept analyzer 145 (FIG. 1), which identifies the conceptsfrom such content. When such concepts are received by the baselineinterest profile generator 710, it maps such concepts to the knowledgearchives 115 and content taxonomy 165 (FIG. 1) and generate one or morehigh dimensional vectors which represent the baseline interest profileof the user population. Such generated baseline interest profile isstored at 730 in the user understanding unit 155. When there is similardata from additional third party sources, the baseline interest profile730 may be dynamically updated to reflect the baseline interest level ofthe growing population.

Once the baseline interest profile is established, when the user profilegenerator receives user information or information related to estimatedshort term and long term interests of the same user, it may then map theuser's interests to the concepts defined by, e.g., the knowledgearchives or content taxonomy, so that the user's interests are nowmapped to the same space as the space in which the baseline interestprofile is constructed. The user profile generator 720 then compares theuser's interest level with respect to each concept with that of a largeruser population represented by the baseline interest profile 730 todetermine the level of interest of the user with respect to each conceptin the universal interest space. This yields a high dimensional vectorfor each user. In combination with other additional information, such asuser demographics, etc., a user profile can be generated and stored in160.

User profiles 160 are updated continuously based on newly receiveddynamic information. For example, a user may declare additionalinterests and such information, when received by the user profilegenerator 720, may be used to update the corresponding user profile. Inaddition, the user may be active in different applications and suchactivities may be observed and information related to them may begathered to determine how they impact the existing user profile and whenneeded, the user profile can be updated based on such new information.For instance, events related to each user may be collected and receivedby the user intent/interest estimator 740. Such events include that theuser dwelled on some content of certain topic frequently, that the userrecently went to a beach town for surfing competition, or that the userrecently participated in discussions on gun control, etc. Suchinformation can be analyzed to infer the user intent/interests. When theuser activities relate to reaction to content when the user is online,such information may be used by the short term interest identifier 750to determine the user's short term interests. Similarly, someinformation may be relevant to the user's long term interests. Forexample, the number of requests from the user to search for contentrelated to diet information may provide the basis to infer that the useris interested in content related to diet. In some situations, estimatinglong term interest may be done by observing the frequency and regularityat which the user accesses certain type of information. For instance, ifthe user repeatedly and regularly accesses content related to certaintopic, e.g., stocks, such repetitive and regular activities of the usermay be used to infer his/her long term interests. The short terminterest identifier 750 may work in connection with the long terminterest identifier 760 to use observed short term interests to inferlong term interests. Such estimated short/long term interests are alsosent to the user profile generator 720 so that the personalization canbe adapted to the changing dynamics.

FIG. 8 is a flowchart of an exemplary process for generating a baselineinterest profile based on information related to a large userpopulation, according to an embodiment of the present teaching. Thethird party information, including both user interest information aswell as their interested content, is accessed at 810 and 820. Thecontent related to the third party user interests is analyzed at 830 andthe concepts from such content are mapped, at 840 and 850, to knowledgearchives and/or content taxonomy. To build a baseline interest profile,the mapped vectors for third party users are then summarized to generatea baseline interest profile for the population. There can be a varietyways to summarize the vectors to generate an averaged interest profilewith respect to the underlying population.

FIG. 9 is a flowchart of an exemplary process for generating/updating auser profile, according to an embodiment of the present teaching. Userinformation is received first at 910. Such user information includesuser demographics, user declared interests, etc. Information related touser activities is also received at 920. Content pieces that are knownto be interested by the user are accessed at 930, which are thenanalyzed, at 950, to extract concepts covered by the content pieces. Theextracted concepts are then mapped, at 960, to the universal interestspace and compared with, concept by concept, the baseline interestprofile to determine, at 970, the specific level of interest of the usergiven the population. In addition, the level of interests of each usermay also be identified based on known or estimated short and long terminterests that are estimated, at 940 and 945, respectively, based onuser activities or content known to be interested by the user. Apersonalized user profile can then be generated, at 980, based on theinterest level with respect to each concept in the universal interestspace.

FIG. 10 depicts an exemplary system diagram for the content ranking unit210, according to an embodiment of the present teaching. The contentranking unit 210 takes variety of input and generates personalizedcontent to be recommended to a user. The input to the content rankingunit 210 includes user information from the applications 130 with whicha user is interfacing, user profiles 160, context informationsurrounding the user at the time, content from the content pool 135,advertisement selected by the ad insertion unit 200, and optionallyprobing content from the unknown interest explorer 215. The contentranking unit 210 comprises a candidate content retriever 1010 and amulti-phase content ranking unit 1020. Based on user information fromapplications 130 and the relevant user profile, the candidate contentretriever 1010 determines the content pieces to be retrieved from thecontent pool 135. Such candidate content may be determined in a mannerthat is consistent with the user's interests or individualized. Ingeneral, there may be a large set of candidate content and it needs tobe further determined which content pieces in this set are mostappropriate given the context information. The multi-phase contentranking unit 1020 takes the candidate content from the candidate contentretriever 1010, the advertisement, and optionally may be the probingcontent, as a pool of content for recommendation and then performsmultiple stages of ranking, e.g., relevance based ranking, performancebased ranking, etc. as well as factors related to the contextsurrounding this recommendation process, and selects a subset of thecontent to be presented as the personalized content to be recommended tothe user.

FIG. 11 is a flowchart of an exemplary process for the content rankingunit, according to an embodiment of the present teaching. User relatedinformation and user profile are received first at 1110. Based on thereceived information, user's interests are determined at 1120, which canthen be used to retrieve, at 1150, candidate content from the contentpool 135. The user's interests may also be utilized in retrievingadvertisement and/or probing content at 1140 and 1130, respectively.Such retrieved content is to be further ranked, at 1160, in order toselect a subset as the most appropriate for the user. As discussedabove, the selection takes place in a multi-phase ranking process, eachof the phases is directed to some or a combination of ranking criteriato yield a subset of content that is not only relevant to the user as tointerests but also high quality content that likely will be interestedby the user. The selected subset of content may also be furtherfiltered, at 1170, based on, e.g., context information. For example,even though a user is in general interested in content about politicsand art, if the user is currently in Milan, Italy, it is likely that theuser is on vacation. In this context, rather than choosing contentrelated to politics, the content related to art museums in Milan may bemore relevant. The multi-phase content ranking unit 1020 in this casemay filter out the content related to politics based on this contextualinformation. This yields a final set of personalized content for theuser. At 1180, based on the contextual information associated with thesurrounding of the user (e.g., device used, network bandwidth, etc.),the content ranking unit packages the selected personalized content, at1180, in accordance with the context information and then transmits, at1190, the personalized content to the user.

More detailed disclosures of various aspects of the system 10,particularly the personalized content recommendation module 100, arecovered in different U.S. patent applications as well as PCTapplications, entitled “Method and System For User Profiling Via MappingThird Party Interests To A Universal Interest Space”, “Method and Systemfor Multi-Phase Ranking For Content Personalization”, “Method and Systemfor Measuring User Engagement Using Click/Skip In Content Stream”,“Method and System for Dynamic Discovery And Adaptive Crawling ofContent From the Internet”, “Method and System For Dynamic Discovery ofInteresting URLs From Social Media Data Stream”, “Method and System forDiscovery of User Unknown Interests”, “Method and System for EfficientMatching of User Profiles with Audience Segments”, “Method and SystemFor Mapping Short Term Ranking Optimization Objective to Long TermEngagement”, “Social Media Based Content Selection System”, “Method andSystem For Measuring User Engagement From Stream Depth”, “Method andSystem For Measuring User Engagement Using Scroll Dwell Time”, “AlmostOnline Large Scale Collaborative Based Recommendation System”, and“Efficient and Fault-Tolerant Distributed Algorithm for Learning LatentFactor Models through Matrix Factorization”. The present teaching isparticularly directed to systems and methods for efficiently matchinguser profiles with audience segments.

In an embodiment, methods and system relate to the placing ofpersonalized advertisement content based on the re-mapping orre-projecting of a weighted user's profile generated from a contenttaxonomy or common feature space such as a universal interest index andknowledge archive into an advertisement audience segment for theplacement of advertising content.

The placement of targeted advertisement based on a user's on-lineviewing is known. However, advertisement content is often skipped byusers because the user does not wish to view advertisements while in themiddle of viewing content. Further, advertisement that is unrelated tothe user's long term interests is often not going to be selected byusers who are seeking personalized content. Similarly, directedadvertisement often underestimates the scope of the user's interestbecause the taxonomy used to classify the advertisement is differentthen the taxonomy used to identify the users' interests. Accordingly, aneed exists for a way to re-project or remap a content taxonomy oruniversal interest space and an advertising taxonomy into a commonrepresentation, to take advantage of the users' interests and injectthat directed advertising content into the users' personalized contentstream so that the user is more inclined to view the personalizedadvertisement.

The present embodiment helps content providers and advertisers targetthe most personalized set of ads to the users. This becomes critical ina personalization experience where ads may be shown in a personalizationstream and the expectation is that a ad that is more personalized to theuser's profile will not seem incongruous and will lead to higherClick-through-rates (CTR) and better user experience.

In an embodiment, the present systems delivers content relevantadvertising in the content stream to maximize the potential userengagement with the advertising. By selecting and personalizingadvertising content and placing it into the content stream, the presentsystem maximizes user interaction with the advertising content. Byre-projecting or remapping user behavioral profiles in a weightedfeature space and by expressing audience segments in the same featurespace, the similarity between the user behavioral profile and theaudience segments can be optimized to direct advertising to a targeteduser base. Post re-mapping, the user can be tagged as belonging to theset of audience segments for which he/she has the maximum similarity tothe targeted audience. By expressing the audience segments in the samefeature space as the user profiles an optimal matching of user profileto advertising can be achieved.

In an embodiment, the commercial intent keywords that are expressive ofan audience segment are expanded via web search, and/or by crawling thead landing pages that are relevant to that audience segment. Byutilizing a machine learned model or through other techniques, a peraudience segment is generated by extracting features, in the same spaceas that of user profile, from web search results or ad landing pages.The model, be it machine learned or otherwise, produces weights thatindicate how important each of the features are to the audience segment.The weighted set of features per audience segment are then matchedagainst user profiles to improve likelihood of conversions.

As part of providing personalized content, and improving a user'sprofile, the user's interactions with the content stream are constantlymonitored to determine which content the user is interested in. In anembodiment of the present disclosure the user's interactions with thecontent stream is utilized to select personalized advertisement contentto inject into the user's content stream.

In an embodiment, a system and method to directly monetize user behaviorby matching user profiles to audience segments is disclosed. In theembodiment, both the user behavioral profiles and the audience segmentsare mapped or re-projected into the same feature space. Mapping the userbehavioral profile and the audience segments into the same space allowsfor the computation of similarity between the two. The user can then betagged as belonging to a set of audience segments for which he/she meetsa similarity threshold. By expressing the audience segments in the samefeature space as the user profiles an optimal matching of user profileto advertising can be achieved.

In an embodiment, the commercial intent keywords that are expressive ofan audience segment are expanded via web search, and/or by crawling thead landing pages that are relevant to that audience segment. These wordsmay be mapped against a specific advertisement taxonomy to maximize thepossible interested segments. By utilizing a machine learned model orthrough other techniques, an audience segment is generated by extractingfeatures, in the same space as that of user profile, from web searchresults or ad landing pages. In this model, be it machine learned orotherwise, weights are produced that indicate how important each offeatures are to the audience segment. The weighted set of features arethen matched against user profiles to improve likelihood of conversions.

When target audiences for online advertising are identified via anadvertisement taxonomy, it is quite likely that the advertisementtaxonomy may use features or descriptors that are very different and areat a different granularity than that of the features representing theuser's behavioral profile. The user's behavioral profile may also berepresented via membership in a content taxonomy or universal interestindex or common feature space. For example, a user who shows an interestin an article related to sports, is more likely to click or browseadvertising that is related to sports or to sports related merchandise,however, the advertiser may wish to broaden the audience to who theadvertisement is shown to include those interested in sports tickets aswell. This additional category may not be explicitly present in theuser's profile. The solution is to remap or re-project features from theuser's profile or the associated content taxonomy or universal interestindex or common feature space and the advertisement taxonomy into thesame feature space.

In an embodiment, as seen in FIG. 12, advertiser 125 wishes to purchaseadvertisement and wishes to target a particular user group, i.e., usersinterested on sports. They may also wish to target user's interested insports tickets. However, the regular content taxonomy 165, may notassociate user A's behavior for sports content as indicating a desire tosee content about sports tickets, where as advertisement taxonomy 127might. Because the advertisement taxonomy 127 does not completelyoverlap with content taxonomy 165 the user's profile alone may not besufficient to personalize advertisement selection from advertisementdatabase 126.

Content/advertisements/user taxonomy correlator 205 must thereforere-project the features representing the user's behavioral profileand/or the associated taxonomy with the advertisement taxonomy. In anembodiment the re-projection may be a manual mapping of the behavioralprofiles into the advertisement taxonomy. In an other embodiment,machine learning can be used to re-project the user behavioral profilesand the advertisement taxonomy into the same space. In still anotherembodiment, parameters such as time between viewing content and viewingadvertisements may be monitored and analyzed to determine correlation,which may then be used to generate the re-projecting algorithm.

In an embodiment, the solution for automated mapping of the users intoad segments has four parts: (1) the user profile representation, (2) thead segment representation, (3) the matching component and (4) theranking component. FIG. 13 represents the steps taken in the re-mappingor re-projecting of the user profile keywords or tokens to theadvertisement audience segments.

FIG. 14 is a representation of the building of a user's profile. In anembodiment, the user profile representation 1300 is personalized by theuser's behavior and is represented by a set of features, key word ortokens. The features, keywords, and tokens can be an ever-growing set ofinterests and terms.

The users profile 160 begins as seen in FIG. 14, each user is assigned auser ID 1400, which identifies the user when they first log into thesystem and tracks the profile. User ID 1400 may have a set of inferredcharacteristics, 1415 associated with it as well as a social networkingprofile 1420. Inferred characteristics may be obtained from the type ofcontent the user views or otherwise interacts with. Inferredcharacteristics may be gleaned based on text in a document or meta-dataassociated with a document. Social networking profile 1420 may containthe information the user has shown an interest in on social networkingsites. This may include likes, shares, follows, etc., as well as thetopics the user shows an interest in. Both the inferred characteristics1415 and the social networking profile 1420 are represented in universalinterest space, a common feature space, for example using a taxonomybased on subject matter or a interest space, for example Wikipedia. Inaddition there may be user demographics, 1425 such as location, gender,age, time of use, can also be made available as a part of the userprofile 160. Similarly, user declared interests 1435, generated by theuser themselves, such as when they create an account may be added to theuser profile index 160. All four of these pieces of information may beused to build a behavioral profile that is then associated with user ID1410.

FIG. 15 depicts the steps taken during the advertisement segmentrepresentation 1302 used to weight the advertisement in terms of theaudience segments. For each advertising segment, the system may firstobtain a set of keywords at step 1500 that represent the commercialinterest of that segment. This set of keywords, for instance, may comefrom the advertiser as in the case of Sponsored Search advertisements,or in the case of Targeting or Look-a-like Modeling, given the segmentof interest, human editors can provide a set that captures thecommercial intent of that segment. That combined with the advertisementcontent extrapolated at step 1502 from the ad database 126 is provide arepresentation of the corresponding ad segmental step 1504. Next, thesystem needs to remap the keywords and features identified for the adsegments in step 1502 to the same feature space as that of the userbehavioral profiles and learn a weight factor in 1508 on each feature.To accomplish the learning, the system utilizes a seed set of commercialkeywords provided by the advertiser or the human editor to gathertraining data for each audience segment. For example, the system may usethe commercial keywords, query a search engine and take the top-k searchresult pages as pages that are representative of the commercial intentof the users. Additionally and/or alternatively, the system may use thelanding pages provided by the advertiser for each segment and extractfeatures in the same space as that of the user behavioral profiles.Given the features extracted from such examples the system can learn theimportance of these tokens in distinguishing the corresponding audiencesegment from the other segments via a machine learned model, say via aclassifier or a language model. Additionally, and/or alternatively, theresults may be analyzed to learn the relationships. At the end of thisprocess, there is a weighted vector computed at step 1508 for eachsegment, in which each component of the vector indicates the importanceof that feature in distinguishing the corresponding audience segment.

Matching component 1304 computes the similarity of the user profile withthat of each advertisement audience segment. The remapping process maybe more efficient by storing each advertisement audience segment weightvectors in a reverse index. Once that is completed, then for eachprofile the system needs to do a O(n) operation where n is the size ofthe user profile, as represented by the number of significant featuresin the user's profile. At the end of this process, the system has ascore indicating the similarity of the user's behavioral profile witheach advertisement audience segment.

Ranking component 1306 is computed based on the similarity score betweenthe user profile and the advertising audience segment, the system canrank the set of advertising audience segments most relevant to the user.This may then incorporate other features such as the expected clickthrough rate, or revenue from ad click, or quality of the advertiser indetermining the ranking along with the relevance of the advertisement tothe user. Thus, the system can make sure that the user is not exposed tonon-relevant ads.

Utilizing this embodiment, the weighted user profile may be remapped orre-projected to match the weighted advertising audience segments toallow for better targeted placement of personalized advertisementcontent.

Personalized advertisement may be presented in many forms. It may beplaced in a banner ad or specific location on a web page or portal pagethe user is accessing. These types of placement, while effective forsome types of advertising may not optimize the likelihood that a userwho is viewing, and used to viewing, personalized content mightconsider, accordingly, advertisements may be placed as part of thepersonalized content stream a user is accessing. When presented as partof the user stream, it is important that the advertisement is related tothe user's interest so that the user does not find it intrusive.In-stream advertisements, may be presented in many ways. It may bepresented as sponsored content, i.e., “this article brought to you by”or dramatized content i.e., video on how to improve your golf putting“brought to you by”, or it may be presented as product reviews orarticles about the products being promoted.

Because of the differences between the feature space of user behavioralprofiles 165 and advertisement taxonomy 127 however,content/advertisement/user taxonomy correlater 205 needs to be able tore-project the user behavioral profiles 165 and the advertisementtaxonomy into a common feature space 127.

FIG. 16 represents a portion of a typical content taxonomy. It is to beunderstood, that this example is limited in the number of levels,categories and subcategories for purposes of clarity and in no way islimited to the specific structure illustrated. FIG. 17 depicts thevarious sources providing general interest representation, includingonline knowledge archives 115 (see FIG. 1) such as Wikipedia,Merrian-Webster Online, Oxford Dictionaries Online, and Dictionary.com,etc., used to develop the universal interest space. Each of sucharchives provides information related to various interests and my beused to build the user's universal interest space. FIG. 18 illustratesthat Wikipedia provides various fine level interest description,including football, peach, Mitt Romney, Barak Obama, Michael Jordan,election, etc.

In an embodiment, the user may be presented with a piece of personalizedcontent related to a US PGA event. The user 105 may then click on thearticle and the user's interactions are conveyed back throughapplication 130. The event is analyzed in user event analyzer 175 andthat information is passed along to user understanding unit 155. Theuser profile for user 105 in 160 is updated indicating the interest inthe golf article. Content/advertisement/user taxonomy correlater 205detects the change in the user profile. The information is passed toadvertisement insertion unit 200 which receives the advertisement fromadvertisement database 126. Advertisement insertion unit 200 conveys theadvertisement information to content ranking unit 210 which then placesthe travel advertisement in the content stream for user 105. In thismanner, personalized advertisement that does not directly match thetaxonomy of the content viewed may be re-mapped to an advertisingtaxonomy and placed in the content stream for the user.

In an other embodiment, other user activities may be used to compute theuser's behavioral profile. In an embodiment, the user understandingsystem looks at the user's mail or other indicators such as posts onsocial media sites like Facebook to detect receipts or other indicia ofon-line purchases. This analysis of past behavior in one taxonomy, i.e.,Smartphone, may be used to map to a completely different taxonomy in theadvertisement taxonomy 127.

FIG. 19 depicts an embodiment of advertisement insertion unit 205. Adinsertion unit 205 comprises in an embodiment, interest re-projector1901, interest identifier 1902, remapped interest 1903, ad contentidentifier 1904 and ad selection unit 1905. Interest re-projector 1901allows inputs from content taxonomy 165 and ads taxonomy 165 and remapsfrom the content taxonomy 165 to the ad taxonomy 127. It is to beunderstood that a universal interest index 1906 may be used in anembodiment with or in place of content taxonomy 165 as the presentdisclosure is not limited to the mapping to a content taxonomy, butembodies a common feature space which may or may not include a taxonomy.The remapping may be based on manual mapping, machine learning, anearest distance algorithm or any other remapping method that theadvertiser 125 may desire. User profiles 160 are inputted intocontent/ads/taxonomy correlator 205 and the user's interest areidentified in interest identifier 1902. The identified interest areremapped based on the taxonomy/interest index re-projections frominterest re-projector 1901 and are remapping into ad interest 1903. Theuser's remapped interest from 1903 are sent to ad selection unit 1905.Ad database 126 send advertising content that may be previouslyidentified based on the ad taxonomy 127 or it may simply be ad contentthat has not been identified or associated with a taxonomy. Ad contentidentifier 1904 identifies the ad content and associates it with adtaxonomy 127 if necessary. Based on the remapped user interest ad.Selection unit 1905 selects the ad to present to user 105 and outputs itto ad insertion unit 200.

To implement the present teaching, computer hardware platforms may beused as the hardware platform(s) for one or more of the elementsdescribed herein. The hardware elements, operating systems, andprogramming languages of such computers are conventional in nature, andit is presumed that those skilled in the art are adequately familiartherewith to adapt those technologies to implement the processingessentially as described herein. A computer with user interface elementsmay be used to implement a personal computer (PC) or other type of workstation or terminal device, although a computer may also act as a serverif appropriately programmed. It is believed that those skilled in theart are familiar with the structure, programming, and general operationof such computer equipment and as a result the drawings should beself-explanatory.

FIG. 20 depicts a general computer architecture on which the presentteaching can be implemented and has a functional block diagramillustration of a computer hardware platform that includes userinterface elements. The computer may be a general-purpose computer or aspecial purpose computer. This computer 2000 can be used to implementany components of the matching user profiles with audience segmentsarchitecture as described herein. Different components of the system inthe present teaching can all be implemented on one or more computerssuch as computer 2000, via its hardware, software program, firmware, ora combination thereof. Although only one such computer is shown, forconvenience, the computer functions relating to the target metricidentification may be implemented in a distributed fashion on a numberof similar platforms, to distribute the processing load.

The computer 2000, for example, includes COM ports 2002 connected to andfrom a network connected thereto to facilitate data communications. Thecomputer 2000 also includes a central processing unit (CPU) 2004, in theform of one or more processors, for executing program instructions. Theexemplary computer platform includes an internal communication bus 2006,program storage and data storage of different forms, e.g., disk 2008,read only memory (ROM) 2010, or random access memory (RAM) 2012, forvarious data files to be processed and/or communicated by the computer,as well as possibly program instructions to be executed by the CPU. Thecomputer 2000 also includes an I/O component 2014, supportinginput/output flows between the computer and other components thereinsuch as user interface elements 2016. The computer 2000 may also receiveprogramming and data via network communications.

Hence, aspects of the method of efficiently matching user profiles withaudience segments, as outlined above, may be embodied in programming.Program aspects of the technology may be thought of as “products” or“articles of manufacture” typically in the form of executable codeand/or associated data that is carried on or embodied in a type ofmachine readable medium. Tangible non-transitory “storage” type mediainclude any or all of the memory or other storage for the computers,processors or the like, or associated modules thereof, such as varioussemiconductor memories, tape drives, disk drives and the like, which mayprovide storage at any time for the software programming.

All or portions of the software may at times be communicated through anetwork such as the Internet or various other telecommunicationnetworks. Such communications, for example, may enable loading of thesoftware from one computer or processor into another. Thus, another typeof media that may bear the software elements includes optical,electrical, and electromagnetic waves, such as used across physicalinterfaces between local devices, through wired and optical landlinenetworks and over various air-links. The physical elements that carrysuch waves, such as wired or wireless links, optical links or the like,also may be considered as media bearing the software. As used herein,unless restricted to tangible “storage” media, terms such as computer ormachine “readable medium” refer to any medium that participates inproviding instructions to a processor for execution.

Hence, a machine readable medium may take many forms, including but notlimited to, a tangible storage medium, a carrier wave medium or physicaltransmission medium. Non-volatile storage media include, for example,optical or magnetic disks, such as any of the storage devices in anycomputer(s) or the like, which may be used to implement the system orany of its components as shown in the drawings. Volatile storage mediainclude dynamic memory, such as a main memory of such a computerplatform. Tangible transmission media include coaxial cables; copperwire and fiber optics, including the wires that form a bus within acomputer system. Carrier-wave transmission media can take the form ofelectric or electromagnetic signals, or acoustic or light waves such asthose generated during radio frequency (RF) and infrared (IR) datacommunications. Common forms of computer-readable media thereforeinclude for example: a floppy disk, a flexible disk, hard disk, magnetictape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any otheroptical medium, punch cards paper tape, any other physical storagemedium with patterns of holes, a RAM, a PROM and EPROM, a FLASH-EPROM,any other memory chip or cartridge, a carrier wave transporting data orinstructions, cables or links transporting such a carrier wave, or anyother medium from which a computer can read programming code and/ordata. Many of these forms of computer readable media may be involved incarrying one or more sequences of one or more instructions to aprocessor for execution.

Those skilled in the art will recognize that the present teachings areamenable to a variety of modifications and/or enhancements. For example,although the implementation of various components described above may beembodied in a hardware device, it can also be implemented as a softwareonly solution. In addition, the components of the system as disclosedherein can be implemented as a firmware, firmware/software combination,firmware/hardware combination, or a hardware/firmware/softwarecombination.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that the teachings may beapplied in numerous applications, only some of which have been describedherein. It is intended by the following claims to claim any and allapplications, modifications and variations that fall within the truescope of the present teachings.

We claim:
 1. A method implemented on a machine having at least one processor, storage, and a communication interface connected to a network for providing content, the method comprising: obtaining a user profile characterizing a user with respect to a first feature space; obtaining information about one or more advertisement audience segments, each of which is associated with at least one advertisement and one or more keywords representing commercial interests associated with the advertisement audience segment; retrieving one or more pieces of content with respect to each of the one or more advertisement audience segments based, at least in part, on the one or more keywords representing the commercial interests associated with the advertisement audience segment, wherein the one or more pieces of content have information consistent with the commercial interests associated with the advertisement audience segment; generating, for each of the one or more advertisement audience segments, an advertisement audience segment profile in a second feature space, based on the corresponding retrieved one or more pieces of content, to characterize the advertisement audience segment; correlating the user profile with each of the advertisement audience segment profiles; selecting one of the one or more advertisement audience segments based on degree of the correlation; and outputting the at least one advertisement associated with the selected advertisement audience segment to the user, wherein the first and second feature spaces correspond to the same feature space.
 2. The method of claim 1, wherein the first feature space is a content taxonomy and the second feature space is an advertisement taxonomy.
 3. The method of claim 1, wherein the first feature space is a universal interest index.
 4. The method of claim 1, wherein the user profile is correlated with each of the advertisement audience segment profiles by mapping at least some of a first set of attributes associated with the user profile to a second set of attributes associated with the advertisement audience segment profile.
 5. The method of claim 4, wherein each of the first set of attributes is assigned with a weight factor with respect to the second feature space, where the weight factor represents importance of the attribute in distinguishing a corresponding advertisement audience segment in the second feature space.
 6. The method of claim 1, further comprising: selecting one of the at least one advertisement for outputting based on at least one of: click through rate of each of the at least one advertisement; revenue associated with each of the at least one advertisement; and quality of each of the at least one advertisement.
 7. The method of claim 1, wherein the at least one advertisement is presented to the user in a content stream, where the content stream includes one or more pieces of content associated with the user profile.
 8. The method of claim 1, wherein the retrieved one or more pieces of content include one or more search result pages obtained by searching based on the one or more keywords.
 9. The method of claim 1, wherein the retrieved one or more pieces of content further include one or more pages linked with the at least one advertisement associated with the advertisement audience segment.
 10. The method of claim 1, wherein generating an advertisement audience segment profile comprises: extracting a set of features from the retrieved one or more pieces of content based on the second feature space; and determining a weight for each of the set of features based on a machine learning model.
 11. A system having at least one processor, a storage, and a communication platform for providing content, the system comprising: a first profile obtainer configured for obtaining a user profile characterizing a user with respect to a first feature space; a second profile obtainer configured for obtaining information about one or more advertisement audience segments, each of which is associated with at least one advertisement and one or more keywords representing commercial interests associated with the advertisement audience segment, retrieving one or more pieces of content with respect to each of the one or more advertisement audience segments based, at least in part, on the one or more keywords representing the commercial interests associated with the advertisement audience segment, wherein the one or more pieces of content have information consistent with the commercial interests associated with the advertisement audience segment, and generating, for each of the one or more advertisement audience segments, an advertisement audience segment profile in a second feature space, based on the corresponding retrieved one or more pieces of content, to characterize the advertisement audience segment; a correlator configured for correlating the user profile with each of the advertisement audience segment profiles and selecting one of the one or more advertisement audience segments based on degree of the correlation; and an output configured for outputting the at least one advertisement associated with the selected advertisement audience segment to the user, wherein the first and second feature spaces correspond to the same feature space.
 12. The system of claim 11, wherein the first feature space is a content taxonomy and the second feature space is an advertisement taxonomy.
 13. The system of claim 11, wherein a piece of content associated with the second feature space is an advertisement.
 14. The system of claim 11, further comprising: selecting one of the at least one advertisement for outputting based on at least one of: click through rate of each of the at least one advertisement; revenue associated with each of the at least one advertisement; and quality of each of the at least one advertisement.
 15. The system of claim 11, wherein the at least one advertisement is presented to the user in a content stream, where the content stream includes one or more pieces of content associated with the user profile.
 16. A non-transitory machine readable medium having information recorded thereon for providing content, wherein the information, when read by a machine, causes the machine to perform the steps of: obtaining a user profile characterizing a user, with respect to a first feature space; obtaining information about one or more advertisement audience segments, each of which is associated with at least one advertisement and one or more keywords representing commercial interests associated with the advertisement audience segment; retrieving one or more pieces of content with respect to each of the one or more advertisement audience segments based, at least in part, on the one or more keywords representing the commercial interests associated with the advertisement audience segment, wherein the one or more pieces of content have information consistent with the commercial interests associated with the advertisement audience segment; generating, for each of the one or more advertisement audience segments, an advertisement audience segment profile in a second feature space, based on the corresponding retrieved one or more pieces of content, to characterize the advertisement audience segment; correlating the user profile with each of the advertisement audience segment profiles; selecting one of the one or more advertisement audience segments based on degree of the correlation; and outputting the at least one advertisement associated with the selected advertisement audience segment to the user, wherein the first and second feature spaces correspond to the same feature space.
 17. The medium of claim 16, wherein the first feature space is a content taxonomy and the second feature space is an advertisement taxonomy.
 18. The medium of claim 16, further comprising: selecting one of the at least one advertisement for outputting based on at least one of: click through rate of each of the at least one advertisement; revenue associated with each of the at least one advertisement; and quality of each of the at least one advertisement.
 19. The medium of claim 16, wherein the at least one advertisement is presented to the user in a content stream, where the content stream includes one or more pieces of content associated with the user profile. 